Air conditioning systems often leak refrigerant. This is undesirable as the system will not operate efficiently with reduced quantities of refrigerant. The refrigerant needs to be replaced. It is also undesirable as refrigerant can be environmentally damaging when released.
Leak detection is generally performed by injecting a fluorescent dye into the air conditioning system. Typically dyes used for this purpose fluoresce in the ultraviolet or near ultraviolet region from approximately 360 to 420 nm; so, an ultraviolet light is shone on the system. Wherever leaks occur the dye will escape the system and fluoresce under the light. A pulsing ultraviolet light for this purpose is described in the inventor's copending U.S. patent application Ser. No. 08/417,234 filed Apr. 5, 1995, and continuations thereof, entitled Fault Locating Device, System and Method. Many other ultraviolet lights are available.
A number of injectors have been developed for getting liquids into an air conditioning system. Some injectors may also be used to inject other liquids, for example, refrigerant or lubricant into the air conditioning system.
U.S. Pat. No. 4,745,772 issued May 24, 1988 to Ferris describes a chemical additive device. The device has a container that unscrews to allow access to the interior for pouring in the additive. The container is screwed back together, the device is connected to the air conditioning system and the additive is injected under pressure from an external charging system.
U.S. Pat. No. 4,938,063 issued Jul. 3, 1990 to Leighley discloses a mist infuser for infusing a fluorescent dye into an air conditioning system. The Leighley infuser has two concentric glass cylinders sandwiched between two circular end caps. Together the end caps and the small cylinder define a reservoir. One end cap has a circular inlet through its centre, while the other has an outlet. An inlet bore opens from the outlet, perpendicular to it, through the circumference of the outlet end cap. Similarly, an outlet bore opens to the inlet from the circumference of the inlet end cap. The bores have respective sealing caps.
In operation, the infuser is turned on its side and the sealing caps are removed. The dye is added through the inlet bore, while air escapes through the outlet bore. The level of the dye is visible through the glass cylinders. The dye is injected under pressure from an external charging system.
In copending application Ser. No. 08/385,643, of one of the inventors of the instant application, Jack Brass, describes an injector having a tubular body surrounding and shielding a glass tube. The body and tube are sealed at opposing ends by a valve coupler and an end fill cap, each with there own O-ring seals. There are three openings through the body to allow for viewing of the contents of the tube, and to allow for light to pass into the tube. The injector is connected at the valve coupler through a hose and an on-off valve to the low side of an air conditioning system. It is connected through the end fill cap to a refrigerant charging system. The valve is shut off and the end fill cap is removed. The body is held upright and the liquid to be injected is poured into the glass tube. The fill end cap is replaced and the valve turned on. An external charging system propels the liquid into the air conditioning system. The tube can be viewed through the openings to determined that a sufficient quantity of the liquid has been propelled from the injector.
As described in a continuation-in-part of the previously mentioned copending application, Jack Brass also teaches that an inline injector can be used as part of an injection loop for injecting liquids into an air conditioning system having a low pressure side port and a high pressure side port. The loop has a first fitting compatible with the low pressure side port, a first control valve, an inline injector having a reservoir for holding a quantity of the liquid, a second control valve and a second fitting compatible with the high pressure side port. The fittings, valves and injector are in sealed fluid connection with one another in the order listed above when the control valves are in open positions. The first valve has an open position and a closed position, and the second valve has a closed position and is able to be opened to allow controlled release of the liquid when the first valve is in the open position.
The use of an injection loop and the pressure differential in the high to low pressure side ports allows liquid to be injected without the use of an external charging system.
Another injector system has been developed to avoid the use of an external charging system. P & F Technologies Limited of Toronto, Canada markets a SpotGun.TM. which is similar to a standard caulking gun. The gun uses a cartridge of 4 oz of fluorescent dye that is stated to be sufficient for 16 applications. The gun can be used for R12 and R134 dye. The cartridge is open and screws into a hose. The gun is operated by manually squeezing a movable trigger against a fixed handle. This forces the dye through the hose into the air conditioning system.
It is an object of the invention to address these or other problems, or to provide alternative devices, for the injection of liquids into pressurized systems.